<label class="container">
    <input type="checkbox" checked="checked">
    <div class="checkmark"></div>
</label>
<style>
/* From Uiverse.io by shreyasm-dev - Tags: neumorphism, checkbox */
/* Hide the default checkbox */
.container input {
  position: absolute;
  opacity: 0;
  cursor: pointer;
  height: 0;
  width: 0;
}

.container {
  display: block;
  position: relative;
  cursor: pointer;
  font-size: 20px;
  user-select: none;
}

/* Create a custom checkbox */
.checkmark {
  position: relative;
  top: 0;
  left: 0;
  height: 1.3em;
  width: 1.3em;
  background-color: #ccc;
  border-radius: 100%;
  background: #e8e8e8;
  box-shadow: 3px 3px 5px #c5c5c5,
              -3px -3px 5px #ffffff;
  transition-duration: 0.5s;
}

.container input:checked ~ .checkmark {
  box-shadow: inset 3px 3px 5px #c5c5c5,
              inset -3px -3px 5px #ffffff;
}

.checkmark:after {
  content: "";
  position: absolute;
  opacity: 0;
}

.container input:checked ~ .checkmark:after {
  opacity: 1;
}

.container .checkmark:after {
  left: 0.45em;
  top: 0.25em;
  width: 0.25em;
  height: 0.5em;
  border: solid darkgray;
  border-width: 0 0.15em 0.15em 0;
  transform: rotate(45deg);
}
</style>
